Hydraulic pitch control device for propellers



Dec. 8, 1953 s. A. FIELDING I 2,661,807

' HYDRAULIC PITCH CONTROL DEVICE FOR PROPELLERS Filed Aug. 28, 1949 3 Sheets-Sheet l INVENTOR. Sterling A. Fielding Dec. 8, 1953 s. A. FlELDlNG 2,661,807

HYDRAULIC PITCH CONTROL DEVICE FOR 'PROPELLERS Filed Aug. 28, 1949 a Sheets-Sheet 2 m i 1 m v 2 w i Q 1' 1 l i i Q s g 28 i i k \r 1 Y \y 5| i i i i r i I, n

I) H 5 l Q i 5 i i I F i 5 4'0 M i GI I0 I) o N INVENTOR. Sterling A. F ieldinq Attorney Patented Dec. 8, 1953 HYDRAULIC PITCH CONTROL DEVICE FOR PROPELLERS Sterling A. Fielding, Portsmouth, Va. Application April .28, 1949, Serial No. 90,213

Claims.

(Granted under Title 35, U. s. Code (1952),

This invention relates to a propeller adjusting mechanism, and more particularly to a hydraulic operating mechanism for changing the pitch angle of a reversible-blade screw propeller.

Heretofore, the servo-mechanism for changing blade pitch was operated by oil supplied from a surge tank kept under air pressure. The operating pressure on the oil was limited by the pressure that could be effectively maintained in the surge tank without excessive leakage through the various valves and packings of the device. This in turn set the maximum working pressure of the fluid which due to its relative w magnitude necessitated the use of large servo-motor cylinders, larger than would be required if higher oil pressures could be used.

If the production of the high fluid pressures required for operating purposes could be limited only to those peak periods when necessary to change the pitch of the blades or vanes, such as during maneuvering periods, excessive leakage could be minimized as the maximum pressures would not have to be constantly maintained.

The present invention, therefore, produces high fluid operating pressures only during those periods within which to effect a desired pitch change.

sec. 266) The present invention is essentially a hydraulic I servo-mechanism, mounted within the propulsion shaft or incorporated in or nearthe hub of th propeller itself, and a variable-stroke hydraulic pump for creating the high fluid presneutral position as the blades reach or assume the desired pitch angle.

The present invention may be utilized in adjusting the blade pitch of a marine propeller as well as those of turbine wheels, pump wheels and similar devices.

It is therefore an object of the present invention to provide a hydraulic operating mechanism in which the operating pressures can be built up as high as necessary within the limits of the parts involved when desired to efiect a pitch change of a propeller.

It is a further object to provide a positive means for adjusting the blade pitch of propeller blades and for holding such part in adjusted positions thereby preventing accidental movement out 01": adjusted positions.

It is an additional object of the present invention to provide a remotely-controlled hydraulic operating mechanism for varying the pitch of propeller blades.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference tothe following detailed description when considered in connection with the accompanying drawings in whichlike referencenumerals refer to like parts throughout the figures and wherein:

Figure 1 illustrates the general organization embodying one form of the invention;

F gure 2 is a cross sectional view through lin 22 of Figure 1';

Figure 3 is a cross sectional view through line 3-3 of Figure 1;

Figure 4 is a cross sectional view through line 4-i of Figure 1; and

Figure 5 is a view similar to Figure 4 but showe ing a modification thereof.

As shownin Figure 1, a hollow propulsion shaft I0 is supported by spaced conventional anti-friction bearings suitablyfmounted on a fixed structure as diagrammatically shown by the parts II and II. The-propulsion shaft I0 terminates in a flange H! to which is'attached a propeller hub body 12. The hub body 12 has a plurality of adjustable propeller blades l3 rotatable on axes perpendicular to the axis of the hub body l2. Each blade is has a'fiange I4 and a crank arm ring I5 secured to it by which the blade can oscillate on an annular ring it secured to the propeller hub body l2.

Securedjte the crank' pin ring I5 is a crank arm I6 havinga crank pin ll journalled in a slide block 18 that is 'slidable in a slot Iii contained in a projection 20 forming part of an extension rod 21; The axis of theslot [9 extends at an angle to theaxis oi the rod 21 as a result of which reciprocation of therod 2i, for a reason to appear, will oscillate the crank arm it which in turn will rotate the blade I3 011' the ring [6 to adjust the pitch of-the blade. 7

The propeller hub I2 is provided with a spider portion 22 supporting one end of the rod 2| and the shaft flange 1 ilsupports the other end. The hub I2 is closed by a head 23 the outer portion of which is formed as a cone 24.

Attached to the extension rod 2| is a piston rod 25 extending rearwardly of the propeller hub andthrough the axial bore ll!" of the propulsion shaft Ill, the rear of which as more clearly shown in Fig. 3 is provided with an enlarged portion 26 having a cylinder bore'21'.-' A piston 28 reciprocates in the cylinder bore 2'! and is attached to a flange 29, forming'partofthe ,piston rod 25, by

bolts 30.

The cylinderzfiiis provided with a flange sn-v against which is abutted a; flange'32 of a cylinder,

head 33 formed with an axially extending stuffing sleeve 34. Supported by the flanges is a gear 35 meshing with a pinion 36 mounted on a shaft 31 driven by a suitable source of power not shown, Bolts 3%! secure the gear 35 and flanges 3|, 32 into a rigid driven unit.

The boreJO- of -thehollowpropulsion shaft l adjacent theey1-1neer"'2 is provided with a piu--- rality of packing rings .39 held in position at one end by a thrust bearing 40, seated against ashoulder 4|, and at the other end by a packing 5 gland 42 held in place by bolts flfi The packing" rings 39 seal off one end of the cylinder 26 while the other end of the cylinder is sealed oflf byt packing glands 44 and 45 fixed in position between stop rings 46 and 49, the latter being fixed to the stufiing.sleeve34.-

The piston 2 8 has an axial bore 50 into which is threaded an inner tube 5|. The rai' ehdofiih'e piston rod 25 is provided with a plurality of passageways 52 and 52' for connecting the forward end pr me cylinder 2 5 With-the axial bore- 5fl=and-- thus pl'aeingtEtn'e innen-tubefi in communication with that 1 end of-the cylinder forxaspurpose #to appear-2i Concentric with the axial bore 50, the pistonis 2o.

provided K with a counterbore: 53 into which is threaded an outer tube -545 The counterbore'd portion of the piston is provided with a plurality of passages 55, 55' directed to the'rearward end of th'e eylinder 26'-=and-:is connected-with the-in terior of the outer tube 54 for a purpose also to appear? The concentric tubes 5| and-54- extend-rearwardlyi-ofi th'e propulsion shaft l U 1 (see- Figure 1) into an injector head 55. As =n1ore-clearly shown in 'Figure ir theinjector head 55 -is :ofsubstantiall y cylindrical -formation-ha-ving sends 51 and 58- which are -enlarged--to-provide: chambers 59-= and Bu ier receivingsfiuid underpressure from flexible-pipingzor hoses 61 and 62-in and for a purpose tobecome apparent;

The inner tube- 5| extends :into? the' injector head 56-and terminates in the fluidchamber: 59-. To prevent leakage of past the tube 5 the intermediate portion 0f -the head 5B is :provided Y with packingv rings- -E3- forced--against ashoulder 64 by: a pack-ings glandfihwhich in turn is held I in place by a packing nut 66 locked byaa'lock nut 61- Although the tube 5| may beformed asa single element, .it -isfor' purposes-of fabrication provided-with a wear extensioni5l' rotating-in the-packing rings 63:

To the forward enlarged end: 58' is bolted astu-fifingboxBBwhich contains a number of pack ing-ringstfiand a-packing .glandJll, .all held-in place by-a packing-nat-1 threaded-on.the-stufiingbox'68 andlocked by alock-*nutJZ-z- Through the packing material 69 =and- |D\ ex-- tends -the outer:- tube s 54 and terminates. within antifriction bearings 'l'3 The innerraces-oi the bearings l3 are fixedte the end of :the outer: tube-54 between a-snap;rinlg$14 and a-locknut 15, V and the outer races of: the bearing a;'r e-- looked in the; enlarged end- 58 between-a shoulder. 16; and an annular flange 11 extending inwardly. from. so the stufiing -box: 6 8

An annular; spider 18" is insertedbetween the J tubes 5 I =a-n d 5dand-is secured to theends' of both in any suitable'rnanner. slgiider'la functions as spaeingmernberfto' maintain the concentricityv 55 of the-tubes. It also actsas a torsion key to prever'it relative twisting between the tubes which must rotate in unison fonareason toappear. The spider 'mis providedlwith' oiieor-more apertures 19 through which fluid'gwithinthe fluid chamber" 70 60 enterstlie outer tube54 for a-purpose to. be ra n "I'he'iiijec'tor head-5s hasi'its rear-ends closed} by." a lioi sin'g. cap 8fl provided'fwith a bifurcated lugs! througnwhicri extends. a; swarmiip- 4 porting rawlink 83 which drives. any suitable indicator 85 for determining the angle 'of adjustment of the propeller blades l3.

The injector head 56 reciprocates during adjustment of the blades l3 for a reason to appear and is therefor'guiddL It is provided with oppositl'y-"extending brackets 85 from which extend upper-and lower stub axles 85, 86 having upper and lower guide rollers 8'! and 81 which ride upon'guidetracksBB, 88' fixed to stationary members 89,39

As'shown in Figure 4, the stub axles 86 and 86' of eachrpairz-extend' above and below the plane oi the tracks 88 and its pair of rollers 81 and 81' engage opposite sides of :their respective track, suchxas-Sfi;

The flexible hoses-5| and 62 are-supplied with. fiuidunder pressure from a variable stroke pump. 93 of a-typesimilarto that illustrated by either Patent .-No. 2,006;880,-issued on July 2, 1935, to

Ben-edeklfor High Pressure Radial Piston.

Hydra-ulic'Pumpzor Motor, orPatent No. 1,965,937,

issued on'July l0; 1934;120 W Ferrisfor Variable Displacement Pump; I

The pumprotor; not shown, of the pump 931s driven througha conventionalcoupling 94' by any suitable device such as-a-motQr- 95'. Asis. CUSEOIHELEY WltI'l variablestroke pumps of thetype.

such as 93, a cradl'eor carrier, not shown, encircles arotatablerotor containing a number of cyl which isfi'xedapivot pin 91. Pi'voted. n the pin 9'! foroscillation is ailver 98 having itsoppositeend portions provided with bifurcated ends 99- and wll. The end..99 is formed with elongated slotsllil through which extend the ends of a pin lfll secured'tothe link '83; The oppositeend I0!!- is similarly;providedwith. elongated slots. Hi3 receiving the ends-of apin .lll 'fixed .to a sleeve. I05

threaded onascrewshaft ilfi rotatably mounted on'fixed bearings .1 UT and I 08.

A gear 09 1s fixed .to thescrew shaft IBBand' meshes Witlia. worm H0 driven by a motor. I I. The motor a i l I is reversible and is suitably: controlldby connection of its leads HZ tosuitabIeswitches, not shown, located at aposition convenien'ttoian operator. The motor H thusdrives the screw shaft B6"ineith'er'direction.

Thestructures ofFi'gures Sand 4 may be simplifiedand the overall length shortenedlintothe construction .ofFigure 5 wherein the propulsion. shaft |2|Fhas fixed thereon a gear lil l'meshing with apinion i22 fixed to a drive shaft I23 driven from asuitable source of'powennot shown;

A hydraulic cylinder i24'is mounted on the opposite end of the propulsion shaft H0 and held thereon against rotation by akey. l25'and' against axial niovefnent by'a n'ut' I25. The hydraulic? cylinder'|24"is;closed byia flange l2] formingpartof a hollow stub shaft IZBJwhichterminates in a flange, ,not shown in Fi'gure' 5 butisimilar to .the

flange |0""of Figure 2' for attachment to a propellet-hub.

Within the hydraulic cylinder i241 is a; piston i28'to whichis bolted a piston rodl 29 equivalent to lpistohrod25'of Figure 2 and functioningin the sa'iiie manner to adjust theprop'eller blades I3. A bearing I30 inserted in the end of shaft I28 cooperates with a, bearing, not shown but similar to the bearing of Figure 2, to support the piston rod |29 for sliding movement. The bearing I30 also provides a fluid-tight joint for the passage of the piston rod I29 out of the hydraulic cylinder I24.

The piston rod I29 adjacent its juncture with the piston is formed with one or more fluid passages I 3|, I32 having a purpose to appear. To insure greater rigidity to the device and to minimize the wear on the cylinder walls, the weight of the piston I28 is partially borne by guide rods I33 secured internally of the cylinder I24.

The web I34 of the piston I28 is'bored at I35 into which is inserted an outer tube I36 and secured into that position by a collar I31 and a nut I38 engaging opposed sides of the web.

The propulsion shaft I20 is formed with an axial bore I39 into which the outer sleeve I36 extends. This sleeve is provided at its ends with a plurality of circumferentially arranged apertures I40 and MI for the passage of fluid as will appear.

Concentrically arranged within the outer tube I36 is an inner tube I42. This inner tube I42 is supported by end spacers I43 and I44 threaded into the ends of the outer tube I36 and sealing the end spacings between it and the inner tube I42. The inner tube I42 is held against axial movement by nuts I45 and I46 threaded on to the ends of the tube I 42 and abutted against the spacers I43 and I44.

The outer sleeve I36 is spaced from the walls of the propulsion shaft bore I39 by a bushing I41 at the open end of the bore and by an annular collar I48 adjacent the rear of the outer sleeve. The bushing I41 and the collar I48 form fluid tight joints between the sleeve and the walls of the bore I 39.

The collar I48 is fixed between ports I49 and I50 formed in the propulsion shaft I20. ports are in communication with annular grooves I5I and I52 contained in the sleeve I53 which is held stationary relative to the propulsion shaft I20. The annular grooves are connected to flexible hoses I54 and I55 which function in the same capacity as the flexible hoses 6| and 62 of Fig-' ure 1.

Fixed to the piston I23 and extending rearwardly from it and through the hydraulic chamber I24 is a follow-up rod I56. This rod is secured to a sleeve I51 encompassing the propulsion shaft I20. The sleeve I51 can slide axially on the propulsion shaft I20 but is prevented from rotating relative to it by a key I58 fixed to the shaft and slidable within a keyway I59 formed in the sleeve I51.

Carried by the sleeve I51 is a collar I66 within which is fixed the outer race of an anti-friction bearing I6I. The inner race of the bearing is fixed to the sleeve I51 by a threaded element I62.

The collar I60 can thus be held stationary relative to the sleeve I51 but can be moved longitudinally of the propulsion shaft I20 with the sleeve I51. The sleeve I51 is provided with diametrically-extending pins I63, of which only one is shown, projecting through elongated slots I64, of which only one is shown, formed in a yoke I terminating the end of a lever I66.

The lever I66 functions identically to the lever 98 of Figure 1, with the yoke I65 corresponding to the bifurcated portion 99 of the lever 98.

These- 6 I OPERATION In Figure 1 the apparatus is shown in neutral position with the propeller blades I3 in inoperative position and the piston 28 centrally positioned within its cylinder 26.

The control motor III may be energized from a remote control mechanism to rotate in either direction and for a, predetermined number of rotations corresponding to the degree of adjustment desired and suitably indicated by an indicator, not shown, in front of the operator.

After the motor I has rotated the screw shaft I06 the predetermined number of turns required to obtain a desired degree of adjustment for the blades I3, the .motor is de-energized thereby stopping the rotation of the screw shaft I08. During rotation of the motor III, the

, threaded shaft I06 will be turned in a direction,

for example, to cause the nut I05 to travel to the left, viewed in Figure 1, to tilt the lever 98 clockwise about the trunnions I02 on the link 83 which at this particular moment is stationary.

The tilting of the lever 98 on the trunnions I02 pushes the slide 94 into the casing of the variable stroke pump 93 which in turn adjusts the eccentricity of the cradle or carrier, not shown. found in pumps of this type, as a result of which fluid under pressure is pumped through hose 6| into fluid chamber 59 (see Figure 4) from whence it flows through the inner tube 5| and out passages 52 (see Figure 3) into cylinder 26 to force the piston 28 toward the cylinder head 33. This movement of the piston 28 is accompanied by movement of the piston rod 25 which, as can be seen in Figure 2, actuates the crank arm I6 to rotate the ring I5 to alter the pitch of the propeller blades I3 to a value between zero or neutral position and maximum positive position.,

Fluid tothe right of piston 28 in chamber 26 is forced out through the passages 55 (Figure 3) into the outer tube 54 and discharged into the oil chamber 60 (Figure 4) for movement, into the flexible tube 62 for return to the variable stroke pump 93.

The movement of the piston 28 to the right (Figure 3) shifts the concentric tubes 5| and 54 in the same direction thereby causing the outer tube 54, through the bearing 16 (Figure 4), to move the injector head 56 to the right. As seen in Figure 1, the movement of the injector head 56 occurs on the rails 88, 88, pushing ahead of it the link 83 and its pins I02.

The shifting of the link 83 to the right causes the lever 98 to be now tilted in a clockwise direction on the trunnions I84 which in turn will withdraw the slide 94 from'the casing of the pump 83, resetting its carrier to a neutral position thereby stopping further adjustment of the blades I3. The blades are held in their adjusted positions by the variable stroke pump 93 for the reason that reverse flow of the fluid is prevented by the pump.

To adjust the blades back to neutral position or to a value between it and maximum negative position, the motor III is energized in a reverse direction causing lever 98 to tilt counterclockwise on the pins I82, as viewed in Figure 1, reversing the flow of fluid. The fluid will be moved by the variable stroke pump 93 through the hose 62 into the outer tube 54 moving the piston 28 to the left, as viewed in Figure 3, and forcing the fluid at the left of the piston 28 out through passages 52, 52' into the inner tube 5| for return to the pump 93, through the hose 6I. The indicator 84 indicates the adjustment of the blades I3 as they 7 are being made asfiwell"as-theadjustment when completed for any particular event. a

""Tliemode or'runcuoniug of "the equipment employing the metzhanism cr-mgure isSubs'tantially the same as thatabove described.

,It is thus seen that'fthei'e' is provided a mechdnism'having a hydraulic devicecapable of building up the necessary"fiuidpressure'for adjusting propeller blades andfor retaining the blades in their adjustedv positions. Includedalsd is a follow-up device for resettingthe hydraulic device to aneutral position.

It should be understood, or course, that although the'foregoirig'disclosure relates to preferred embodiments of theinvention, numerous modifications or alterations may be made therein without departing from thespirit and the scope of .the invention as set forth in the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes Without the payment of any royalties thereon and therefor.

Having thus described the invention, what is claimed is: I

-1.'-In a hydraulic-operating mechanism comprising "in combination, a control motor, a threaded shaftd1'iven thereby, a nut on said threaded shaft adapted to travel longitudinally thereof upon rotation thereof, a variable stroke fluid pump, a control system including means integral with said pump for'varying the quantity anddii'ectionof fluid pumped thereby, a lever mounted for pivotable movement adjacent said pump, pivotable' connecting-means connected at one end to said leverand at the other end to said means integral with said pump an injector head having a pluralityof oil-receiving chambers, flexible conduits connecting said variable stroke pump with said oil-receiving chambers, means respectively connecting opposite ends of said layer to said nut and said injector head, a hollow rotating propulsion shaft, a cylinder incorporated in said propulsion shaft, a piston slidable in said cylinder, a propeller having adjustable blades mounted on said propulsion shaft, means actuated by said piston and extending through said propulsion shaft for adjusting said blades, concentric tubes extending into said injector head, anti-friction means connecting one-of said tubes with said injector head for reciprocating movement therewith, each of said-tubes respectively extending into'said oil-receiving chambers and through said propulsion shaft,-means securing said tubes to said piston, said piston having passages respectively placing said-tubes in-communication with opposite. ends of said cylinder.

2. In a hydraulic operatingmechanism comprisingin combination, a variable stroke fluid pump, a-control system for varying the quantity and direction of fluid pumped thereby, a movable injector head having a plurality of 'valveless oil receiving chambers, flexible conduits connecting said variable stroke pump with said oil receiving chambers, a hollow rotating propulsion shaft, a cylinder incorporated in saidpropulsion shaft, a piston slidable in said cylinder, a propeller hub having adjustable blades mounted on said propulsion shaft, means actuated by said piston and extending through said propulsion .shaft for adjusting said blades, fluidsupply means interconnecting said piston with said movable in-.

jector head for supplying pressurefluidto-said piston and whereby movement. of said piston causes a corresponding'changdfin thefpositlonbf said injector head-*and-a follow-'up -system coinprising means connecting said=movable injector head with-said control system whereby unovement of said i-njector head-in response-to e. change in position Qfsaid-piston makes operative said follow-up system for cutting ofi supplymf fluid from said pump.

3. The combination-according to claim2'wherein said control system comprisesa controlmotor adjacent said'pump for driving a threaded shat-t, a nut onsaidshai-t, aprctruding member connec-ted'withs'aid" variable stroke pump, ands-said follow-up system comprises'a"link pivoted on said member"and 'interconnectmg said injector head and said' nut; whereby movement or sa' id injector head actuates "said control :system 'for cutting off the supply of i'iu'id' to'said' o'il' receiving chambers.

4. The combination acco'rding'to claim'2'wherein said fluid suppiy"means comprises" a pairnf concentric tubes respectively "connecting "said chambersin"said 'injector head with the :iorward and after sides of said piston, a pair' 'of tracks in alignment with said shaft, ahdmea ns mountingsaidmovame injector head onsaid tracks for reciprocating movement in hdrwaid and reverse-"direction.

5. In combination, a hydraulic opratinmecha'nism for controllingthepitch of propeller blades comprising, a hub having a plurality of va'r'ia'ble pitch propeller blades, a hollow propulsion shaft connected to said hub, a cylinder incorporatewm said shaft, 'a piston in said cylinder; apistonr'od in said hollow shaft, means connecting -sa'id-piston rod at oneend-to said piston andat; the other end to said bladesfor changing the pitch of said blades; a hollow movable injector head ad'- jacent said cylinder, inner and outer concentric tubes affixed in said' injector head, means connecting said innerand outer tubes with said piston, a first'fiuidohamber formed by'the walls of said innertube and theforward sidefof said piston, a second fluid'chaniber formed'bythe walls of said outer tube and 'the"aft er side of said piston, a "variable "stroke-"pumpffiuid supply and return lines respectively connecting said pump with said first and second fluid chambers, directional flow ineansconnected to ssiapump for selectively directing the discharge therefrom through either of said supply or return1lines;and follow-up "means interconnecting said movable injector head'with said-directional fiow ineans, whereby fluidsupplied by said: pu-mp to either of said firstor second fluid chambers movessaid piston in an ahead or rearward direction-thereby controlling the pitch of said blades.

STERLING A FIELDING.

References Cited in theme *of -this patent UNITED sTATEsPA'TEN'Ts Number Name -Date 2,244,770 =Englesson" l June 10, -1941 2,307,039 Hammond -Jan. -'5,- 1943 2,307,849 Mullen Jan. 12,1943 2,382,389 Benedek l Aug. '14, 1945 FOREiGNPAT-ENTS Number Country Date 343,653 GreatBritain Feb] 26,"i31 449,407 Great Britain une-'2s,'1c3e 479,888 Great Britain urebiiijiese s-saozc Great Britain- -June it, 15943 

